Posable Tensegrity-Constrained Inflatable Kinematic Graphical Analysis

Author(s):  
Adeline Wihardja ◽  
Kunj Patel ◽  
Laura Giner Munoz ◽  
Ellen Kim ◽  
Jonathan Luntz ◽  
...  

Abstract Inflatable devices have been used in various applications due to their low cost, light weight, simplicity, and ability to compactly stow yet deploy to large sizes with complex shape. Recently, soft robotics has added active shape change to inflatables’ otherwise static functionality. However, the required complex multi-chamber structures and active pressure control sacrifice many inherent advantages including simplicity and stowability. Many applications require only passive shape change (posability), where users manipulate a device manually, and the device simply holds its new posed shape. This paper explores a new approach using internal string-like tensile elements to provide posability while maintaining stowability and other inherent advantages of inflatables, leveraging concepts in the field of tensegrity mechanisms. Tensegrity constrained inflatables provide posable motion by allowing internal tensile strings to thread through loops as the shape is changed, where friction between the strings and loops retain the new pose. Graphical instantaneous center kinematic analysis techniques for traditional linkage systems are extended to include threaded tensegrity mechanisms, enabling analysis and design of complex posable tensegrity structures. A simple example prototype implementing bending with 1 DOF, demonstrates posable behavior, quantified in terms of the force required to change pose at different angles and pressures. The resulting bistable behavior is explained using the IC kinematic analysis. The kinematic techniques are also applied to the design of one degree of freedom functional building blocks which combine to create tensegrity configurations providing 2 DOF posability in two and three dimensions which are demonstrated through multiple hardware prototypes. The novel technology and design methods presented in this paper provide a foundation for the development of a class of new user-interactive inflatable devices with posable functionality and deploy and stow capability.

Author(s):  
A A Fogarasy ◽  
M R Smith

The present paper introduces a much simplified method for the kinematic analysis of epicyclic gear drives. It is based on the concept of the existence of only two basic building blocks and their kinematic constraint equations. These can easily be found by inspection of the relevant kinematic structural diagram. A new type of notation is used which is simpler and more versatile than those of previous methods and is adaptable to depicting the kinematic alternatives of any particular drive without the need for drawing structural diagrams.


2020 ◽  
Vol 30 (Supplement_5) ◽  
Author(s):  
◽  

Abstract The European Commission's State of Health in the EU (SoHEU) initiative aims to provide factual, comparative data and insights into health and health systems in EU countries. The resulting Country Health Profiles, published every two years (current editions: November 2019) are the joint work of the European Observatory on Health Systems and Policies and the OECD, in cooperation with the European Commission. They are designed to support the efforts of Member States in their evidence-based policy making and to contribute to health care systems' strengthening. In addition to short syntheses of population health status, determinants of health and the organisation of the health system, the Country Profiles provide an assessment of the health system, looking at its effectiveness, accessibility and resilience. The idea of resilient health systems has been gaining traction among policy makers. The framework developed for the Country Profiles template sets out three dimensions and associated policy strategies and indicators as building blocks for assessing resilience. The framework adopts a broader definition of resilience, covering the ability to respond to extreme shocks as well as measures to address more predictable and chronic health system strains, such as population ageing or multimorbidity. However, the current framework predates the onset of the novel coronavirus pandemic as well as new work on resilience being done by the SoHEU project partners. This workshop aims to present resilience-enhancing strategies and challenges to a wide audience and to explore how using the evidence from the Country Profiles can contribute to strengthening health systems and improving their performance. A brief introduction on the SoHEU initiative will be followed by the main presentation on the analytical framework on resilience used for the Country Profiles. Along with country examples, we will present the wider results of an audit of the most common health system resilience strategies and challenges emerging from the 30 Country Profiles in 2019. A roundtable discussion will follow, incorporating audience contributions online. The Panel will discuss the results on resilience actions from the 2019 Country Profiles evidence, including: Why is resilience important as a practical objective and how is it related to health system strengthening and performance? How can countries use their resilience-related findings to steer national reform efforts? In addition, panellists will outline how lessons learned from country responses to the Covid-19 pandemic and new work on resilience by the Observatory (resilience policy briefs), OECD (2020 Health at a Glance) and the EC (Expert Group on Health Systems Performance Assessment (HSPA) Report on Resilience) can feed in and improve the resilience framework that will be used in the 2021 Country Profiles. Key messages Knowing what makes health systems resilient can improve their performance and ability to meet the current and future needs of their populations. The State of Health in the EU country profiles generate EU-wide evidence on the common resilience challenges facing countries’ health systems and the strategies being employed to address them.


Author(s):  
DU Hui ◽  
GAO Feng ◽  
PAN Yang

A novel 3-UP3R parallel mechanism with six degree of freedoms is proposed in this paper. One most important advantage of this mechanism is that the three translational and three rotational motions are partially decoupled: the end-effector position is only determined by three inputs, while the rotational angles are relative to all six inputs. The design methodology via GF set theory is brought out, using which the limb type can be determined. The mobility of the end-effector is analyzed. After that, the kinematic and velocity models are formulated. Then, workspace is studied, and since the robot is partially decoupled, the reachable workspace is also the dexterous workspace. In the end, both local and global performances are discussed using conditioning indexes. The experiment of real prototype shows that this mechanism works well and may be applied in many fields.


2021 ◽  
Author(s):  
Trishna Patel ◽  
Jamie Hendren ◽  
Nathan Lee ◽  
Aaron D Mickle

AbstractStudying the visceral sensory component of peripheral nervous systems can be challenging due to limited options for consistent and controlled stimulation. One method for mechanical stimulation of hollow organs, including colon and bladder, are controlled distensions mediated by compressed air. For example, distension of the bladder can be used as an assay for bladder nociception. Bladder distension causes a corresponding increase in abdominal electromyography, which increases with distension pressure and is attenuated with analgesics. However, the hardware used to control these distensions are primarily all one-off custom builds, without clear directions how to build your own. This has made it difficult for these methods to be fully utilized and replicated as not everyone has access, knowledge and resources required to build this controller. Here we show an open-source Arduino based system for controlling a solenoid valve to deliver timed pressure distensions in the experimental model. This device can be controlled by one of two methods through direct TTL pulses from the experimenters data acquisition software (ex. CED Spike2) or by a graphical user interface, where the user can set the time before, during, and after distension as well as the number of cycles. This systems low cost and relative ease to build will allow more groups to utilize timed pressure distensions in their experiments.Specifications table


Author(s):  
Hagninou E. V. Donnou ◽  
Drissa Boro ◽  
Donald Abode ◽  
Brunel Capo-Chichi ◽  
Aristide B. Akpo

The design of a vertical axis wind turbine (Darrieus type) adapted to the site of Cotonou in the coastal region of Benin was investigated. The statistical study of winds based on the Weibull distribution was carried out on hourly wind data measured at 10 m above the ground by the Agency for the Safety of Air Navigation in Africa and Madagascar (ASECNA) over the period from January 1981 to December 2014. The geometrical and functional parameters of the wind turbine were determined from different models and aerodynamic approaches. The digital design and assembly of the wind turbine components were carried out using the TOPSOLID software. The designed wind turbine has a power of 200W. It is equipped with a synchronous generator with permanent magnets and has three wooden blades with NACA 0015 profile. The optimal coefficient of lift and drag were estimated respectively at 0.7832 and 0.01578. The blades are characterized by an optimum angle of attack estimated at 6.25° with a maximum fineness of 49.63. Their length is 4 m and the maximum thickness is estimated at 0.03 m with a chord of 0.20 m. The volume and mass are respectively equal to 0.024 m3 and 36 kg. The aerodynamic stall occurs at an attack angle of 14.25°. The aerodynamic force exerted on these blades is estimated to be 240 N. The aerodynamic stresses exerted on the rotor are estimated at 15 864 504 Pa and the solidity at 0.27. The efficiency of the wind turbine is 0.323. From TOPSOLID, the geometrical shape of each component of the wind turbine is represented in three dimensions. The assembly allowed to visualizing the wind turbine after export via its graphical interface. The quantity of annual energy produced by the wind turbine was estimated at 0.85 MWh. This study is the first to be carried out in the study area and could reduce the technological dependence of vertical axis wind turbines and their import for low cost energy production.


Author(s):  
Ghazi Qaryouti ◽  
Abdel Rahman Salbad ◽  
Sohaib A. Tamimi ◽  
Anwar Almofleh ◽  
Wael A. Salah ◽  
...  

The three-dimensional (3D) printing technologies represent a revolution in the manufacturing sector due to their unique characteristics. These printers arecapable to increase the productivitywithlower complexity in addition tothe reduction inmaterial waste as well the overall design cost prior large scalemanufacturing.However, the applications of 3D printing technologies for the manufacture of functional components or devices remain an almost unexplored field due to their high complexity. In this paper the development of 3D printing technologies for the manufacture of functional parts and devices for different applications is presented. The use of 3D printing technologies in these applicationsis widelyused in modelingdevices usually involves expensive materials such as ceramics or compounds. The recent advances in the implementation of 3D printing with the use of environmental friendly materialsin addition to the advantages ofhighperformance and flexibility. The design and implementation of relatively low-cost and efficient 3D printer is presented. The developed prototype was successfully operated with satisfactory operated as shown from the printed samples shown.


Author(s):  
Mazhar Ul Haq ◽  
Zhao Gang ◽  
Fazl E. Ahad ◽  
Anees Ur Rehman ◽  
Muhammad Hussain

In this paper, inverse kinematic analysis of a proposed three link mechanism of a bio-inspired micro scanning device towed underwater by a surface vessel to actuate its aileron fins for its depth control and for its stabilization against roll is performed. Mechanism is actuated by IPMC actuators. To speed up the design verification process, computer aided simulations are used to perform motion analysis of the proposed IPMC actuated mechanism through Pro/Mechanism tool. Inverse kinematic analysis is performed to find out the joint variables of the mechanism to realize fin actuation along desired path. Displacements, velocities and accelerations of the links constructing mechanism are found out to establish their interrelationship. Results are analysed for the study of mechanism efficacy and for sizing the IPMC actuators. This paper contributes to introduce a new approach of virtual prototyping using advanced simulation tools for analysis and design verification of IPMC actuated mechanisms for biomimetic applications before moving into functional prototype stage.


Sign in / Sign up

Export Citation Format

Share Document